Field of the Invention
The present invention pertains to self-blunting needle devices and, in particular, to holders for blood collection needles.
Conventional blood collection systems are known in the art to comprise a holder, typically in the form of a generally cylindrical shell, that holds a double-ended needle cannula. One end of the needle cannula extends forward from the holder and is used for venipuncture (the "venipuncture needle") while the other end (the "filling needle") extends into the holder and is used to puncture the seal cap on a sample fluid collection tube (which, typically, is vacuum-sealed). The device is used by unsheathing the venipuncture needle and effecting venipuncture and then inserting the sealed end of a collection tube into the holder and pushing the seal cap against the boot that covers the tip of the filling needle. The filling needle pierces the boot and the seal cap and blood is drawn into the collection tube. If additional samples are required, the first collection tube is removed and a second collection tube is pushed into the holder in its place. When the last tube is filled, the blood collection needle is withdrawn from the patient's vein.
Prior art self-blunting blood collection needles have provided a deployable, locking, blunting member to protect the user against inadvertent needle sticks but required the user to engage in an extraneous manipulation of the sample tube in order to deploy the blunting member such as the insertion of the sample tube past a discernible "stop" point at which the collection tube is already fully engaged by the filling needle. There is need, therefore, for a self-blunting needle mechanism that does not require manipulation beyond that which is familiar to medical technicians with the use of conventional blood collection needles.